Diesel in Petrol tank

[stanleykirk]

Facts: I have a Tucson Hybrid PHEV, 22 plate. It broke down (not the first time) on 25th March. Today (13th April) the dealer calls me to say that this time the cause is contaminated fuel, basically diesel in the petrol tank.

Questions:
(1) The previous fuel top-up was 20th March. How does contaminated fuel take 5 days before the running of the car is affected?
(2) How is it possible to fit a wide diesel nozzle in a narrow petrol tank filler? Online I find that this is possible with a small number of cars. Is this Tucson one of those, i.e. a serious design flaw?

The current rough estimate to fix is north of £10K.

[old man]

So what are you actually saying. You mistakenly put diesel into a petrol car, or that the petrol you put in the car was contaminated with diesel from the filling station pump ?
Diesel in a petrol car is not as bad as vice versa as diesel has lubricating properties, whereas petrol doesn't and acts like a cleaner in the engine and other parts.
If you put the diesel in, then I don't understand why it took 5 days to manifest itself, unless you didn't drive the car much. If the petrol was contaminated with diesel, then it would have taken a while to show up, and again it depends on how far the car was driven.

£10000 seems exhorbitent to fix it, but I have heard of large figures like this being quoted for higher end cars where petrol has been used instead of diesel.
If the petrol was contaminated at source, then you should have a claim against the supplying garage. If you put diesel in the tank by mistake, unless your car insurance will cover the cost, then you're up the creek with a big bill looming.
If it's a dealer quoting £10000, you could get it fixed cheaper at an independent garage as long as they use genuine Hyundai parts

[Pogleswood]

Where did you buy the fuel from?, by us recently a major supermarkets E10 was contaminated with diesel from allegedly the tanker driver miss filling the tanks.

[old man]

How is it possible to fit a wide diesel nozzle in a narrow petrol tank filler? Online I find that this is possible with a small number of cars. Is this Tucson one of those, i.e. a serious design flaw?

Having reread this, it seems pretty apparent from your above comment that you misfueled your car.
It was very easy to misfuel in the past as any nozzle would fit any filler hole, Nowadays it's not so easy, but still possible on some cars, as you've found out.
You won't be able to get around this by claiming a design fault. You, as the owner have a duty of care and nobody forced you to use the wrong fuel.